This invention relates to an electrolytic processing cell for use in a variety of electrolytic processes including various electroplatings such as zinc electroplating and tin electroplating, electrolytic polishing, and electrolytic cleaning.
A zinc electroplating apparatus is described as one typical example of prior art electrolytic processing apparatus by referring to the accompanying drawings. FIG. 12 is a partially cross-sectional side elevation of a prior art horizontal zinc electroplating apparatus generally designated at 1'. FIG. 13 is a cross section taken along lines XIII--XIII in FIG. 12. The apparatus 1' includes a plating cell 5', support members 40, a pair of upper and lower electrodes 8' and 7' suspended by the support members so as to be disposed in the cell, conducting rolls 19 disposed in the cell for guiding and transferring a strip 37 to be plated across the electrodes and through the cell and for conducting electricity to the strip, a pair of nozzles 18 for supplying plating solution toward the strip between the electrodes, and conductors 39 electrically connected to the electrodes for conducting electricity to the electrodes. Zinc electroplating is carried out by passing the strip 37 between the upper and lower electrodes 8' and 7', injecting plating solution from the nozzles 18 toward the strip 37 between the electrodes, and conducting electricity across the strip 37 and the electrodes 8', 7' through the rolls 19 and the conductors 39.
The zinc electroplating apparatus 1' illustrated is designed such that the electrodes 8', 7' are suspended by the support members 40 from outside the cell 5'. Then the conductors 39, 39 for supplying electricity to the electrodes 8', 7' must be extended from outside the cell 5' along the suspending members 40 until they are connected to edge portions of the electrodes 8', 7'. Undesirably, longer the conductors, the more is the electric resistance and hence, the power loss.
The prior art zinc electroplating apparatus 1' illustrated in FIGS. 12 and 13 encounters another problem in replacing the electrodes 8', 7'. Because of the construction illustrated, the strip 37 in the cell 5' must be cut before the lower electrode 7' can be removed from the cell for replacement. A relatively long time is required for such replacement, that is, the down time in which the continuous plating or processing line is interrupted is long enough to lower productivity.
Another example is illustrated in FIGS. 14 and 15. FIG. 14 is a partially cross-sectional side elevation of a prior art vertical zinc electroplating apparatus generally designated at 3'. FIG. 15 is a cross section taken along lines XV--XV in FIG. 14. The apparatus includes cell segments 20' separated by vertical partitions, conducting rolls 27, dip rolls 33 disposed in the cell segments, and vertically extending electrodes 38 spaced apart from each other in a horizontal direction. A strip 37 is passed through the cell while it is alternately trained around the conductor rolls 27 and the dip rolls 33. The vertical zinc electroplating apparatus 3' also encounters a problem in replacing those electrodes 38 located adjacent the cell partitions. The conducting rolls 27 must be removed and the strip 37 must be cut before the electrodes 38 can be removed from the cell 20'. The plating line is interrupted for a relatively long time for such replacement, resulting in a loss of productivity.
Electricity is usually supplied to the electrodes 38 by connecting conductors 41 to support members 42 from which the electrodes 38 are suspended. Then the internal resistance of the support members 42 increases the overall power loss. Even when the conductors 41 are directly connected to the electrodes 38, the length of the conductors 41 must be increased as in the horizontal zinc electroplating apparatus illustrated above, also resulting in an increased power loss.
An improved electroplating apparatus is proposed in Japanese Patent Application Kokai No. 58-7000 in which electrodes can be replaced without cutting a strip in a plating cell. The apparatus, however, employs a rather complicated structural design for electrode replacement, and the replacing operation is cumbersome. The apparatus has not eliminated the drawback of an increased power loss because long conductors are still required for electricity supply.